title: Accelerated respiratory response to moderate exercise in late pregnancy.
abstract: We studied the rates of change of expired ventilation (VE, BTPS), O2 consumption (VO2, STPD) and CO2 production (VCO2, STPD) at the start and stop of 6 min of 50-W bicycle exercise, comparing 20 healthy young women at 38 weeks of pregnancy (G) and 3 months postpartum (NG). VO2, VCO2 and VE were significantly greater at rest for G than for NG. The absolute increases of VO2 and VCO2 from steady-state rest (SSR) to steady-state exercise (SSE) were the same for G and NG. The absolute increase of VE from SSR to SSE was significantly greater for G than NG. VCO2 and VE increased more rapidly in G than NG, but only during the first 90 sec of exercise. Recovery rates after exercise were equal for G and NG. We believe that lower extremity muscles of G contract on more distended veins at the onset of exercise, forcing increased volumes of venous blood through the lungs, increasing VO2 and VCO2. VE follows VCO2 closely.
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism; D005260:Female; D006801:Humans; D009132:Muscles / Q000098:blood supply / Q000378:metabolism; D010101:Oxygen Consumption; D005082:Physical Exertion; D049590:Postpartum Period; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012039:Regional Blood Flow; D012119:Respiration
chemical_list: D002245:Carbon Dioxide